I just listen to Beyerdynamics DT770 (250ohms) headphones via Ifi Zen Dac via an old half working Acer Aspire laptop. Hardly 'decent HiFi' yet listening to Beethoven's 2nd or 4th movement of 3rd Symphony of Youtube is absolutely exhilarating for me, maybe because I have not heard anything more 'highend' which you most probably use. Maybe ignorance is bliss and a lot cheaper.
Klassik is not even sure if it's a case of "ignorance is bliss." Klassik has compared classical CDs/SACDs of albums in Klassik's collection and compared them YouTube 160k Opus versions of the same albums using the same equipment. The CDs do sound a little bit better at least in the sense that they are a tad bit more 'open' sounding. A tad bit. Klassik only knows of the difference when comparing the two back-to-back.
Even with armed with that knowledge that CD quality is a tad bit better than YouTube quality, Klassik never feels that Klassik's listening experience on YouTube is any less enjoyable. If Klassik likes something Klassik hears on YouTube, Klassik will thoroughly enjoy it. Klassik does not perform any fewer pelvic thrusts, dance steps, or air conducting from the YouTube source than the CD source.
Klassik has heard sources where there is an obvious loss in fidelity. Poor quality cassettes, Ronco/Ktel-type LPs where they put too much music on one side of the record, low bitrate MP3s, and so forth where it's obvious that the quality is far from where it would be from a better quality source. Even then, Klassik might still enjoy the music just the same if it's really good music even if Klassik is left wanting more with the sound quality. That really doesn't describe Klassik's listening on YouTube though.
Klassik quite likes John Eliot Gardiner's HIP interpretations of Beethoven's symphonies. Gardiner's Beethoven symphony CDs came out quite a long time back and the audio quality is not so great. Those came from a time when DG/Archiv's recording quality was rather spotty. Fortunately, Gardiner has performed the symphonies for TV in more recent times. The audio quality and the performance quality are arguably better. Klassik quite enjoys these and they are, you guessed it, YouTube.
Klassik also has some Beethoven symphony recordings performed by Anton Nanut and some Slovenian orchestera. Yes, these are recordings from cheap supermarket classical CDs that sold for $3.99 USD at supermarkets in the 1980s. xD The sound quality is not great, but it is not poor either. It's a pretty typical 'meh' 1980s digital recording. The performance quality is excellent though and Klassik prefers it to just about any big-name conductor or orchestra who has performed Beethoven symphonies. Others might disagree, of course, but the point is that the sound quality of the recordings or the fact that they are cheap supermarket CDs does not stop Klassik from thoroughly enjoying the performance.
There are some classical music dinosaurs who are stuck in the past paradigm of heavy record label marketing where the only good recordings are ones performed by the likes of Bernstein and Karajan. :doh: Younger listeners, and astute older listeners, know especially now that this is London and that there are a lot of great performances from unexpected sources. These great performances may exist on many different streaming sites and media, but in all probability, YouTube is the most reliable place to find them.